The colour of the sky deepened as the sun went down.

太阳下山时天空的颜色变暗。

youdao

I lay lazily smoking and studying the colour of the sky, as we call the void of space, from where it showed a reddish grey behind the pines to where it showed a glossy blue-black between the stars.

我懒懒的躺着吸烟，观察天空的颜色，在我们所说的太空空间里，在松树林后面的那一片是微红的灰色，星与星之间则是泛着光泽的深蓝。

youdao

The search lights and the fireworks made the sky a kaleidoscope of colour.

探照灯和焰火使得天空的颜色千变万化。

《新英汉大辞典》

The colour of the sea changes as the light advances up the sky.

BBC: Sardinia, land and sea